Method for transceiving channel state information in wireless access system, and apparatus for supporting same

Abstract

The present invention relates to a wireless access system that supports massive MIMO, and provides a method for transceiving channel state information (CSI) for operating the massive MIMO and an apparatus for supporting said method. The method for transmitting CSI by a terminal in a wireless access system that supports massive multi-input multi-output (MIMO), according to one embodiment of the present invention, may comprise the steps of: receiving a signal including report period information; receiving downlink data including a reference signal; measuring first CSI using the reference signal; acquiring second CSI using the first CSI; and reporting the first CSI or the second CSI to a base station based on the report period information. According to the present invention, the first CSI may be information on a first antenna set including antennas for transmitting the reference signal, and the second CSI may be information on a second antenna set including antennas not transmitting the reference signal.

What is claimed is: 
     
       1. A method of transmitting channel state information (CSI) by a user equipment in a wireless access system supportive of a plurality of antennas, the method comprising the steps of:
 receiving, from a base station, reporting period information; 
 receiving, from the base station, a reference signal via a first antenna set of the plurality of antennas of the base station; 
 generating first CSI for the first antenna set using the reference signal; 
 obtaining second CSI for a second antenna set of the plurality of antennas based on the first CSI and spatial correlation between the first antenna set and the second antenna set; and 
 reporting, to the base station, the first CSI and the second CSI based on the reporting period information, 
 wherein the first CSI comprises an information on the first antenna set including antennas configured to transmit the reference signal, and 
 wherein the second CSI comprises to an information on the second antenna set including antennas configured to not transmit the reference signal. 
 
     
     
       2. The method of  claim 1 , wherein the reporting period information comprises at least one of an information on a reporting period and a reporting time for the first CSI and an information on a reporting period and a reporting time for the second CSI. 
     
     
       3. The method of  claim 2 , wherein the reporting period and the reporting time for the first CSI are independent from the reporting period and the reporting time for the second CSI. 
     
     
       4. The method of  claim 1 , wherein the reporting period information comprises an information on a reporting period and a reporting time for the first CSI only, and
 wherein a reporting period and a reporting time for the second CSI are determined based on the reporting period and the reporting time for the first CSI. 
 
     
     
       5. A user equipment for transmitting a channel state information (CSI) in a wireless access system supportive of a plurality of antennas, the user equipment comprising:
 a receiver; 
 a transmitter; and 
 a processor; 
 wherein the processor is configured to:
 control the receiver to receive, from a base station, a reporting period information, 
 control the receiver to receive, from a base station, a reference signal via a first antenna set of the base station, 
 generate first CSI for the first antenna set using the reference signal, 
 obtain second CSI for a second antenna set of the base station based on the first CSI and spatial correlation between the first antenna set and the second antenna set, and 
 control the transmitter to report, to the base station, the first CSI and the second CSI based on the reporting period information, and 
 
 wherein the first CSI comprises an information on the first antenna set including antennas configured to transmit the reference signal, and 
 wherein the second CSI comprises an information on the second antenna set including antennas configured to not transmit the reference signal. 
 
     
     
       6. The user equipment of  claim 5 , wherein the reporting period information comprises at least one of an information on a reporting period and a reporting time for the first CSI and an information on a reporting period and a reporting time for the second CSI. 
     
     
       7. The user equipment of  claim 6 , wherein the reporting period and the reporting time for the first CSI are independent from the reporting period and the reporting time for the second CSI. 
     
     
       8. The user equipment of  claim 5 , wherein the reporting period information comprises an information on a reporting period and a reporting time for the first CSI only, and
 wherein a reporting period and a reporting time for the second CSI are determined based on the reporting period and the reporting time for the first CSI. 
 
     
     
       9. The method of  claim 1 , wherein the spatial correlation is obtained based on an angle of arrival (AOA) of a transmission signal, an azimuth spread (AS) value of the transmission signal and a distance between the plurality of antennas. 
     
     
       10. The method of  claim 1 , wherein the second CSI is obtained by interpolating channel state corresponding to the first CSI or by applying minimum mean square error (MMSE) estimation on the channel state corresponding to the first CSI. 
     
     
       11. The method of  claim 10 , wherein the MMSE estimation is applied on the channel state corresponding to the first CSI by using a cross correlation vector between the first antenna set and the second antenna set and using an auto correlation vector between the channel state corresponding to the first CSI. 
     
     
       12. The user equipment of  claim 5 , wherein the spatial correlation is obtained based on an angle of arrival (AOA) of a transmission signal, an azimuth spread (AS) value of the transmission signal and a distance between the plurality of antennas. 
     
     
       13. The user equipment of  claim 5 , wherein the second CSI is obtained by interpolating channel state corresponding to the first CSI or by applying minimum mean square error (MMSE) estimation on the channel state corresponding to the first CSI. 
     
     
       14. The user equipment of  claim 13 , wherein the MMSE estimation is applied on the channel state corresponding to the first CSI by using a cross correlation vector between the first antenna set and the second antenna set and using an auto correlation vector between the channel state corresponding to the first CSI.